what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

This started after over a month of normal workin, yesterday at 4:30pm I got chopped about and it took over an hour before service resumed. Tonight I get chopped several times, the interleaving kept changeing and the snr is still flapping wildly at least 10db excursions. I have got back a very low speed limited service! has someone unleashed the wretched dlm on me again, if so please dissable it again now!!

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

Thank you telephone support after 35 minutes of mind numbing muzac someone helped me by "resetting some parameters" result 4Mbps/6db and snr flapping has stopped! will watch like a hawk, seems to me the dslam needed a firm poke in the ***** as not even the dlm could cause this frequency of snr changes and there were no dropouts anyway! (see attached pic).

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

Not out of the woods yet!! This morning flapping around again, rate down to 800Kbps, interleaving almost removed! Restored a reasonable service by modem reboot only to be followed a while later by pair of REIN events that suspended service due to 3K/min crc error rates, phone QLT fine (no crackles etc) all info posted on fault ticket.

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

And to answer my own question the fault appears to have been dirty contacts once again INSIDE the new BT master socket fitted by them at the beginning of the year, lots of switch cleaner and plugging/unplugging has reduced the snr ripple to the normal <0.5db. OR its a nasty coincidence and the fault will recur in a few hours/days, lets see!

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

Well yes and no! there is no doubt it was very active as the interleave kept changing and as usual it's activities tend to disguise the real fault. My major concern was that as has happened before BT destroy the settings carefully crafted by myself and Pnet that keeps this line operational, unfortunately not everybody in Pnet understands this so it is necessary to bring it to there notice every time the line goes crazy! I have certainly had situations before where snr fluctuations such as REIN are further amplified by dlm behavior so it continues to be highly suspect every time such things start to happen on this line. Ohh yes I have REIN but nobody is willing to do anything about it except I did manage to persuade the BT engineer to shift the drop cable away from the power cable and that has reduced the REIN amplitude by 3db but that's a whole other story

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

The DLM does not set the exact interleave depth. It sets a minimum INP value. The exact interleave depth and other framing parameters (such as amount of FEC data and block size) will be worked out by the modem to achieve the specified INP level. Probably the interleave depth was changing because the speed had dropped so low, but the INP value remained the same.

Re: what are you doing to my internet, 2nd day of service failures, speed down from 5000kbps-800kbps

Ahhh my mistake! I thought only the dlm set the interleave directly, learn something everyday BUT I am no less suspicious of it (I expect irrationally in your opinion), perhaps I just have a very bad history with it